1. Field of the Invention
The present invention relates to a piezoelectric/electrostrictive ceramic actuator. In particular, the present invention relates to a piezoelectric/electrostrictive ceramic actuator with a multilayered suprastructure and a piezoelectric/electrostrictive layer.
2. Description of the Prior Art
An actuator should move quickly with sufficient displacement to deliver ink drops if a specific size and at a specific speed from an ink jet printer head.
It is a general practice that an ink jet printer head actuator comprise a vibration plate bound with infrastructure, a lower electrode formed on the vibration plate, a piezoelectric/electrostrictive layer formed on the lower electrode, and an upper electrode formed on the piezoelectric/electrostrictive layer.
For an actuator so comprised, if electricity is supplied to the upper and lower electrodes, piezoelectric/electrostrictive layer placed between the electrodes vibrates according to the electricity, cycling between deformation and restoration.
The usual piezoelectric/electrostrictive ceramic actuator structure is illustrated in FIG. 1.
It is a general practice in the actuator shown in FIG. 1: to form on the vibration plate (12) a lower electrode (14) of platinum etc. and a chamber plate (10) made of zirconia etc.; to form a piezoelectric/electrostrictive layer (16) on the lower electrode (14) using ceramic oxide powder, which requires heat treatment at high temperature, as it has been prepared by ordinarily used solid phase process; and to form an upper electrode (18) of silver etc. on the piezoelectric/electrostrictive layer (16).
For such actuators, only a few materials which endure heat treatment above 1000xc2x0 C. can be used as material of a vibration plate or a chamber plate, because a piezoelectric/electrostrictive layer is formed of ceramic oxide powder requiring a heat treatment above 1000xc2x0 C. So there is a disadvantage that sorts of material usable for the vibration plate or the chamber plate are limited.
Voltage above a certain value should be applied to exert a proper displacement, because it is formed of one layer. The voltage supplied for the actuator to exert the displacement must be high, because the particle size of ceramic oxide powder prepared by solid phase process is relatively large, 0.2-2 xcexcm, so that the piezoelectric/electrostrictive layer formed is 20-30 xcexcm thick.
The driving voltage of piezoelectric/electrostrictive ceramic actuator for use in an ink jet head is dependent upon the properties of the substance comprising the actuator, including actuator thickness, piezoelectric/electrostrictive material properties, vibration plate characteristics etc. and is determined within a range that can produce sufficient displacement speed. Such a driving voltage of the piezoelectric/electrostrictive ceramic actuator for an ink jet head is generally within a range near 20-30 V.
Greater driving speed and displacement is required for the ink jet printer head to function as a high performance printer head. But a method ordinarily used to get greater driving speed and displacement is to increase the drive voltage, in which case the drive circuit unit price for manufacture is increased, and there is another problem that bad product can occur, because it must endure higher process voltages.
The purpose of the present invention is to provide a manufacturing method of a piezoelectric/electrostrictive ceramic actuator capable of high speed and large displacement vibration by manufacturing a multilayered piezoelectric/electrostrictive ceramic actuator using ceramic paste feasible of low temperature formation of piezoelectric/electrostrictive layer.
The invention, to accomplish the purpose, features a manufacturing method of a multilayered piezoelectric/electrostrictive ceramic actuator made by a sintering process at low temperature, the method comprising the steps of: providing a metal vibration plate; forming a piezoelectric/electrostrictive layer on the vibration plate using ceramic paste prepared by mixing ultrafine ceramic oxide powder below 5 xcexcm of particle size made by a nonexplosive oxidative-reductive combustion reaction at a relatively low temperature of 100-500xc2x0 C., having basic composition elements of lead and titanium, and ceramic sol solution of the same or similar composition with the ultrafine ceramic oxide powder, prepared on a base of water or organic solvent; thermally treating the piezoelectric/electrostrictive layer at 100-800xc2x0 C.; forming an upper electrode on the piezoelectric/electrostrictive layer; and repeating the steps of forming a piezoelectric/electrostrictive layer on the vibration plate, thermally treating the layer, and forming an upper electrode on the layer, whereby multilayered piezoelectric/electrostrictive layer and upper electrode are formed.
The invention features a manufacturing method of a multilayered piezoelectric/electrostrictive ceramic actuator by a sintering process at low temperature, the method comprising the steps of: providing a vibration plate; forming a lower electrode on the vibration plate; forming a piezoelectric/electrostrictive layer on the lower electrode top using ceramic paste prepared by mixing ultrafine ceramic oxide powder below 5 xcexcm in particle size made by a nonexplosive oxidative-reductive combustion reaction at a relatively low temperature of 100-500xc2x0 C., having basic composition elements of lead and titanium, and ceramic sol solution of the same or similar composition with the ultrafine ceramic oxide powder, prepared on a base of water or organic solvent; thermally treating the piezoelectric/electrostrictive layer at 100-800xc2x0 C.; forming an upper electrode on the piezoelectric/electrostrictive layer; and repeating the steps of forming a piezoelectric/electrostrictive layer on the vibration plate, thermally treating the layer, and forming an upper electrode on the layer, whereby multilayered piezoelectric/electrostrictive layer and upper electrode are formed.
The invention also features a multilayered piezoelectric/electrostrictive ceramic actuator manufactured by a sintering process at low temperature, the actuator comprising: a metal vibration plate; a piezoelectric/electrostrictive. Layer on the vibration plate using ceramic paste prepared by mixing ultrafine ceramic oxide powder below 5 xcexcm of particle size made by a nonexplosive oxidative-reductive combustion reaction at a relatively low temperature of 100-500xc2x0 C., having basic composition elements of lead and titanium, and ceramic sol solution of the same or similar composition with the ultrafine ceramic oxide powder, prepared on the base of water or organic solvent; and an upper electrode formed on the piezoelectric/electrostrictive layer, wherein a multilayer structure is formed by forming the piezoelectric/electrostrictive layers and the upper electrodes alternatively of each other.
The invention also features a multilayered piezoelectric/electrostrictive ceramic actuator manufactured by a sintering process at low temperature, the actuator comprising: a vibration plate; a lower electrode formed on the vibration plate; a piezoelectric/electrostrictive layer on the lower electrode using ceramic paste prepared by mixing ultrafine ceramic oxide powder below 5 xcexcm of particle size made by a nonexplosive oxidative-reductive combustion reaction at a relatively low temperature of 100-500xc2x0 C., having basic composition elements of lead and titanium, and ceramic sol solution of the same or similar composition with the ultrafine ceramic oxide powder, prepared on the base of water or organic solvent; and an upper electrode formed on the piezoelectric/electrostrictive layer, wherein a multilayered structure is formed by forming the piezoelectric/electrostrictive layers and the upper electrodes alternatively of each other.